5 research outputs found
Pickering Membranes Stabilized by Saturn Particles
We
report on a novel method to synthesize particlescalled
by us <i>Saturn particles</i>having two hydrophobic
caps that oppose each other and are separated from each other by a
hydrophilic belt that encircles the particle. Mixtures of these particles
with water and air, without the usage of low molar mass surfactants,
easily form Pickering foams and Pickering membranes that are stable
for days. These Pickering membranes are composed of a thin film of
water into which the particles are embedded in such a way that the
belt is surrounded by the water and the caps protrude out of the water
into the air at the top and bottom side of the water film. As expected
for a liquid membrane, these Pickering membranes are permeable for
gases, with the permeance being proportional to the solubility and
diffusion coefficient of the gas considered. Experimentally obtained
permeance values agree reasonably well with theoretical calculations
Dehydroergosterol as an Analogue for Cholesterol: Why It Mimics Cholesterol So Wellor Does It?
Although
dehydroergosterol (DHE) is one of the most commonly used
cholesterol (CHOL) reporters, it has remained unclear why it performs
well compared with most other CHOL analogues and what its possible
limitations are. We present a comprehensive study of the properties
of DHE using a combination of time-resolved fluorescence spectroscopy,
quantum-mechanical electronic structure computations, and classical
atomistic molecular dynamics simulations. We first establish that
DHE mimics CHOL behavior, as previous studies have suggested, and
then move on to elucidate and discuss the particular properties that
render DHE so superior. We found that the main reason why DHE mimics
CHOL so well is due to its ability to stand upright in a membrane
in a manner that is almost identical to that of CHOL. The minor difference
in how DHE and CHOL tilt with respect to membrane normal has only
faint effects on structural membrane properties, and even the lateral
pressure profiles of model membranes with CHOL or DHE are almost identical.
These results suggest that the mechanical/elastic effects of DHE on
the function of mechanically sensitive membrane proteins are not substantially
different from those of CHOL. Our study highlights similar dynamical
behavior of CHOL and DHE, which implies that DHE can mimic CHOL in
processes with free energies close to the thermal energy
EFSUMB Gastrointestinal Ultrasound (GIUS) Task Force Group: Celiac sprue and other rare gastrointestinal diseases ultrasound features
Transabdominal gastrointestinal ultrasound (GIUS) is unique in its capacity to examine the bowel non-invasively and in its physiological condition, including extra-intestinal features such as the splanchnic vessels, mesentery, omentum and lymph nodes- even at the bedside. Despite this, and its extensive documentation for its usefulness, it has only been fully implemented in a few European countries and expert centres. Therefore, the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) established a GIUS Task Force Group in 2014 consisting of international experts from 9 European countries with the objectives to standardize and promote the use of GIUS in a clinical setting. This is achieved by publishing clinical guidelines and recommendations on indications and use of GIUS and so far,4 guidelines have been published: first on “examination techniques and normal findings”, second on “inflammatory bowel disease”, third on “acute appendicitis and diverticulitis” and fourth on “transrectal and perineal ultrasound”